Snowmobile with banking control

ABSTRACT

The skis are mounted on the lower ends of support columns or posts connected to a transverse beam pivoted on the centerline. In one modification the beam is a leaf spring and, when the steering column is turned, the control cages between the leaf spring and the ramps are moved in opposite directions to tilt the beam and retract the inside ski while moving the outside ski away from the body. This forces the body to bank or lean into the turn. In the other modification the beam is rigid and the turning motion is transmitted by a chain to jackscrews to tilt the beam.

United States Patent Asmussen [4 1 Mar. 21, 1972 [54] SNOWMOBILE WITH BANKING CONTROL [72] Inventor: Hans P. Asmussen, 2126 North 26th Street, Milwaukee, Wis. 53205 I969, abandoned.

[52] U.S. C1. ..l80/5 R, 280/21 R 51 ..'.B62m 27/02 [58] Field ot'Search ..l80/3, 4, 5, 6; 280/21 R [56] References Cited UNITED STATES PATENTS 2,700,427 1/1955 Schomers 180/3 2,905,479 9/1959 Schomers Milward ..180/5 3,550,706 12/1969 Watkins 180/5 FOREIGN PATENTS OR APPLICATIONS 986,197 3/1951 France 180/3 Primary Examiner-Richard J. Johnson Attorney-John W. Michael, Gerrit D. Foster, Bayard M. Michael, Paul R. Puerner, Joseph A. Gemignani, Andrew 0. Riteris and Daniel Van Dyke s7 ABSTRACT The skis are mounted on the lower ends of support columns or posts connected to a transverse beam pivoted on the centerline. In one modification the beam is a leaf spring and, when the steering column is turned, the control cages between the leaf spring and the ramps are moved in opposite directions to tilt the beam and retract the inside ski while moving the outside ski away from the body. This forces the body to bank or lean into the mm. In the other modification the beam is rigid and the turning motion is transmitted by a chain to jackscrews to tilt the beam.

6 Claims, 8 Drawing Figures Patented March 21, 1972 3,650,341

4 Sheets-Sheet 1 Patented March 21, 1972 3,650,341

4 Sheets-Sheet z Jul ado) %w L? flsumsszw Patented March 21, 1972 Jm/emor 3h; flsmuasaa 4 Sheets-Sheet 5 Patented March 21, 1972 4 Sheets-Sheet SNOWMOBILE WITH BANKING CONTROL CROSS-REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part of my application, Ser. No. 795,648, filed Jan. 3 l 1969 and now abandoned.

BACKGROUND OF INVENTION When turning a snowmobile the operator must use considerable body lean to offset the tendency of the body to roll over under the influence of centrifugal force. The snowmobile corners flat" and the rolling tendency is pronounced. It has been recognized that it would be desirable to have. the body bank during a turn but no designs have been successful.

SUMMARY OF INVENTION The present steering mechanism carries the skis at the lower ends of guided columns or posts protruding. from the underside of the front of the snowmobile body. In the firstmodification the upper ends of these posts engage a transverse leaf spring and this gives the spring action for both front skis. The leaf spring functions as a beam pivoted on the centerline of the snowmobile and the pivoting action is controlled by the steering mechanism. When the steering handle bar is turned, a control cage operating on a ramp is withdrawn from under one side of the pivot while a similar cage is forced under the other side whereby the entire spring (beam) is tilted so as to, in effect, withdraw one of the ski-supporting posts into the body while pushing the other out of the body and thereby force the body to lean into the turn. If these posts were mounted vertically the skis would go around the turn flat but by inclining the posts rearwardly the skis also bank or edge.

The amount of body lean or banking imparted during the turn is adjustable to suit the particular requirement and particularly permitting the mechanism to be adjusted for higher speed turns in which greater banking is desired.

In the second modification the beam is rigid and is tilted by means of jackscrews driven by a chain actuated by the steering column. This arrangement permits fewer parts and reduces wear while reducing the steering force required of the operator.

DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of the snowmobile.

FIG. 2 is a fragmentary, sectional view of the first modification steering mechanism from the side.

FIG. 3 is a front view of the steering mechanism of FIG. 2.

FIG. 4 is a top view of the first modification with the front of the snowmobile being at the bottom of this view.

FIG. 5 is a sectional, side view (line 5-5 in FIG. 7) of the second modification.

FIG. 6 is a side view (line 6-6 in FIG. 7).

F IG. 7 is a rear view with parts broken away.

FIG. 8 is a top, plan view (the front being at the bottom of the view).

DESCRIPTION OF PREFERRED EMBODIMENTS The snowmobile has a body 10 provided with a seat 12 and driven by the track 14 which, in accordance with the usual practice, is mounted on the body through bogey wheels which permit the body to lean relative to the track. The operator steers by means of the handle bar 16 orany steering mechanism desired. Normally a steering wheel is not used since the amount of turn imparted is not so great as to require the use of a steering wheel. In the first modification (FIGS. 1-4) the skis 18 are carried at the lower end of posts 20 protruding from the front underside of the body. The skis are pivotal about an axis transverse the snowmobile body to allow them to follow the contours. The posts 20 are guided in sleeves 22 and are rearwardly inclined, as may be seen clearly in FIGS. 1 and 2. The upper end of each post is rounded to present a generally spherical surface which is bored and tapped to receive bolt 24 which passes through the slotted end of leaf spring 26 and also through washer 28. Spring 30 is compressed between the underside of the bolt and the top of the leaf spring. The spring'acts to provide a resilient, beam-like connection between the posts 20 and the leafspring while providing sufficient snugness to minimize rattle. It will be noted that the leaf spring includes three leaves 32,34,36 which are bolted together at the center and connected to the bridge member 38 pivoted on bolt 40 which lies in'a fore and aft direction. Leaf spring 36 provides a resilient support for the skis and cushions the ride. As the posts 20 move up and down, the spring is worked and the slot 42 accommodates the rela tive movement required by this working.

It will be noted the bridge member has depending fore and aft ribs 44. Each rib is supported by a roller 46 pivotally mounted in-cage 48 which carries two additional rollers-50,52 which ride on the inclined ramp 54. This ramp, in turn, is sup ported between the front and back plates 56,58 of the support column. The front of each'cage is connected by a link 60 (ineluding an adjustable turn buckle arrangement or the like 62) to the control bar 64 near the front of the body. This bar is fixed to the front end of nonrotatable relative to) the fore and aft control arm 66 which is welded to the steering column 68. Therefore, as the steering column is turned, the control arm 66 turns and, since the bar 64 is fixed relative to arm 66, it is moved bodily so as to pull one roller cage 48 forward while pushing the other .aft. This results in forcing the entire leaf spring-beam 26 to tilt in a direction opposite to the direction in which the body should lean. This, in effect, allows the inside ski to move closer to the body and at the same time forces the other ski further from the body with the result that the body itself is forced to bank or lean into the turn. The degree of banking imparted in this manner is adjustable by simply changing the point at which the connecting link 60 connects to the bar 64. In FIG. 4 the links are shown connected to the outermost of the three holes and this will give the greatest degree of banking in the turn. If the manner in which the snowmobile is driven does not normally call for this high degree of banking,

the links 60 can simply be reconnected to give a more comfortable degree of banking commensurate with the manner in which the snowmobile is driven.

The fore and aft control arm- 66 must, of course, be connected to the skis to impart the turning action. For this purpose the steering links 70 are connected to the control arm 66 by means of ball and socket connections 76. This will allow pivotal action of the link 70 relative to the control arm. The outboard end of each link 70 is provided with a ball and socket connection 72 to the arm 78 through post 74. The arm 78 is keyed, splined, or otherwise fixed on the upper end of the post. Therefore, as the steering column is turned, the control arm66 is rotated about the axis of the steering column to force the steering arm 78 to rotate the post which carries the ski. Since the post 20 is inclined rearwardly, the ski itself is forced to bank or to edge, that is to force the inside edge of the ski downwardly to obtain better bite during the turn.

In FIG. 4 the front of the vehicle is at the bottom. This, therefore, means that the steering column (and control arm 66) will be rotated in a counterclockwise direction in a left turn. The cross bar 64 is moved bodily at the front end of the arm 66 so as to pull the right side cage 48 forward while pushing the left side cage aft, which lowers the right side of the leaf spring 26 and raises the left side. This forces the right side post 20 down out of the body while allowing theleft side post to retract into the body. Therefore, the body itself is forced to lean to the left. Since the lean is forced, the outside ski is loaded more than the left and turning control is improved.

It will be understood that during this action, of course, the control arm has actuated links 70 to, in turn, act on the steering arms 78 to force the skis to turn relative to the body. By reason of the inclination of the posts, the skis will edge, that is in this left turn the left edge of each ski will be lower than the right edge.

While the construction shown in FIGS. 1-4 operates quite well, it suffers in having many parts and requiring significant force to hold the snowmobile in a turn. Further, the springtype beam 26 results in constant working of the posts 20 in their sleeves with consequent wear considerations. The second modification has been worked out to overcome these problems and is the preferred construction. In this arrangement the skis 118 are provided with springs 116 in the conventional manner and the posts 120 are slideable and rotatable in sleeves 122 provided with gudgeon pins 124 journaled in bearings 125 fixed in the body 110. This allows the sleeves to rock slightly as required during a turn. The posts (and skis) move vertically in the sleeves only during a turn since the upper ends of the posts are connected to arigid beam 126 (as compared to the spring beam of FIGS. l-4) pivoted at 140 on the centerline of the body. The outboard ends of thebeam are provided with sockets 128 receiving the balls 130 on the upper ends of the posts. As the beam 126 is rocked about axis .140, one post (and ski) is retracted while the other projects further from the body, thus forcing the body to bank or lean into the turn.

The rocking movement of beam 126 is controlled by a simple arrangement. Cross arm 166 fixedon column 168 will, of course, rotate about the axis of column 168 as it is turned. The ends of cross arm 166 are connected by a chain 170 which engages the sprockets 172,174 fixed on the left and right (FIGS. 7 and 8) jackscrews 176,178. The upper end of each jackscrew threads through a sleeve 180 provided with gudgeon pins 182 journaled in bearings 184 carried by the beam while the lower ends of the jackscrews thread through sleeves 186 journaled in bearings fixed in the pedestal 156 for movement about the axis of pins 188. If the steering column is rotated clockwise (FIG. 8), the chain 170 will rotate the sprockets 172,174 to, in effect, elongate jackscrew 176 while shortening jackscrew 178 to rock beam 126 about 140 in a clockwise direction (FIG. 7). This retracts the left ski (FIG. 7) and projects the right ski, and the snowmobile will bank.

The steering motion is simple. Arm 132 is welded to the steering column and projects rearwardly. Each post 120 is provided with a trailing steering arm 134 clamped to the upper end of the post and having a ball 136 at its free end received in socket 138 on link 102, which also has a ball and socket con nection to arm 132. Therefore, turning the steering column clockwise (FIG. 8) moves both steering arms clockwise and turns the skis-while the body is forced to bank or lean into the turn.

The jackscrews require less force to rock the beam and steering is much easier in this version. Also, the thread pitch can be selected to be non-reversible so little or no force is required to hold the turn while the first modificationrequires constant holding force during the turn.

While 1 have not yet made the following design, it is visualized that a chain and sprocket arrangement actuated by the steering column can turn a horizontal lead screw threaded through an arm depending from the beam. The ends of the lead screw can be supported in ball bearings to insure easy turning.

I claim:

l. A snowmobile including a body having a drive track and front mounted skis for steering and provided with means for causing the body to bank during a turn, comprising,

means mounting the skis on the body for steering movement and for movement towards and from the body, I the mounting means for each ski including a post slidable relative to the body and rotatable to effect turning movement, said posts being interconnected by transverse beam means pivoted for rocking movement about an axis generally on the centerline of the body, steering means for imparting steering movement to the'skis, means responsive to turning movement of the steering means to force the ski on the outside of the turn from the body while retracting the inside ski towards the body to force the body to bank or lean into the turn, the distance the skrs are moved from and retracted towards the body being increased as the turning movement is increased.

2. A snowmobile according to claim 1 in which the means responsive to turning movement controls the tilt of the beam means.

3. A snowmobile according to claim 2 in which the means controlling the tilt of the beam means includes adjustable support means engaging the beam means on opposite sides of said axis and actuated by the steering means.

4. A snowmobile according to claim 3 in which the adjustable support means on each side includes a jackscrew and the jackscrews are oppositely pitched.

5. A snowmobile according to claim 4 including a sprocket on each jackscrew and a chain engaging the sprockets and actuated by the steering means to actuate the jackscrews equally.

6. A snowmobile according to claim 2 in which the beam means is tilted by a screw device actuated by the steering means. 

1. A snowmobile including a body having a drive track and front mounted skis for steering and provided with means for causing the body to bank during a turn, comprising, means mounting the skis on the body for steering movement and for movement towards and from the body, the mounting means for each ski including a post slidable relative to the body and rotatable to effect turning movement, said posts being interconnected by transverse beam means pivoted for rocking movement about an axis generally on the centerline of the body, steering means for imparting steering movement to the skis, means responsive to turning movement of the steering means to force the ski on the outside of the turn from the body while retracting the inside ski towards the body to force the body to bank or lean into the turn, the distance the skis are moved from and retracted towards the body being increased as the turning movement is increased.
 2. A snowmobile according to claim 1 in which the means responsive to turning movement controls the tilt of the beam means.
 3. A snowmobile according to claim 2 in which the means controlling the tilt of the beam means includes adjustable support means engaging the beam means on opposite sides of said axis and actuated by the steering means.
 4. A snowmobile according to claim 3 in which the adjustable support means on each side includes a jackscrew and the jackscrews are oppositely pitched.
 5. A snowmobile according to claim 4 including a sprocket on each jackscrew and a chain engaging the sprockets and actuated by the steering means to actuate the jackscrews equally.
 6. A snowmobile according to claim 2 in which the beam means is tilted by a screw device actuated by the steering means. 